Vikings running back Dalvin Cook exited early in the third quarter of Sunday’s 27-26 loss to the Seattle Seahawks after pulling up during a run and grabbing his left groin.

He tried to shake it off, returning for one snap before ceding his workload to Alexander Mattison.

Coach Mike Zimmer said Cook will undergo an MRI on Monday. Cook immediately went to the locker room after pulling up on his 22nd touch of the night, a swing pass to the flat. He started hobbling before reaching the sideline, where he was knocked out of bounds by Seahawks safety Ryan Neal.

Cook returned for one play, an interception by quarterback Kirk Cousins.

The injury marked a momentum shift. The Vikings punted, and Seahawks quarterback Russell Wilson threw a 19-yard touchdown pass on the next drive. Seattle took a 14-13 lead before Cook’s brief return, and Seahawks running back Chris Carson scored to make it 21-13 after the interception.

“Obviously, you don’t want to lose a guy like Dalvin,” receiver Adam Thielen said. “He’s such a dynamic football player and means so much to this offense.”

The Vikings had to find a way without Cook, the NFL’s leading rusher entering Week 5. He was again the offense’s centerpiece, compiling 21 touches by halftime, and had 65 rushing yards and 24 receiving yards before exiting.

While the Vikings built a 13-0 lead, Cook and Mattison combined for 128 of 217 first-half yards.

Mattison finished with career highs of 20 carries and 112 rushing yards, 99 of which came after halftime while the Vikings offense wore down the Seahawks defense. But Mattison was stopped for no gain on the final fourth-down run at Seattle’s 6.

“Good backs, you don’t question them too much,” Zimmer said. “You just let them do what they do, and he’s a good back.”

Rookies stick

First-round rookie cornerback Jeff Gladney showed off his feistiness in a third-quarter shoving match with Seahawks receiver D.K. Metcalf, showing the fire that has probably helped keep him in the starting lineup despite Mike Hughes’ return.

Zimmer chose to start the two rookies — Gladney and Cameron Dantzler — again at cornerback while Hughes, the 2018 first-round pick, returned from a two-game absence due to a neck injury. But Hughes was relegated to a smaller role as the third corner, on the outside in nickel packages. Gladney took Hughes’ spots in the base defense and defended the slot in the nickel.

Cornerbacks Holton Hill (foot injury) and Kris Boyd (hamstring) did not play.

Wilson stars

Before the Vikings’ failed fourth-down run, linebacker Eric Wilson made the heads-up play to push Carson out of bounds. This prevented Carson from being the first person to touch a forward pass, before Wilson made the leaping interception off Wilson in the fourth quarter.

Wilson had six tackles, two tackles for losses, a sack and the interception.

“I knew [Carson] was close out of bounds, [Wilson] was probably going to scramble, so I pushed him out,” Wilson said. “Got my head back around. I think [Eric Kendricks] got some pressure on him and I see the ball and I just went up and made the play on it.”

Samia struggles

Right guard Dru Samia had a horrific night, getting flagged four times (one declined) while Seahawks defensive tackle Jarran Reed did just about whatever he wanted in moments. Samia drew three holding penalties, continuing to look out of sorts while filling in for injured Pat Elflein.

Zimmer said he felt good overall about the offensive line’s play against Seattle, but he told the NBC broadcast at halftime they needed to “change protections” to deal with Reed.

Falcons fire GM, head coach

After a 23-16 loss to the Panthers, the winless Falcons on Sunday night fired General Manager Thomas Dimitroff and head coach Dan Quinn — a week before a scheduled visit to U.S. Bank Stadium.

The Vikings played the Texans just before Houston fired GM and coach Bill O’Brien, and Minnesota will host the Falcons in Atlanta’s first game under an interim coach to be announced Monday.

Etc.

• The Vikings’ pass rush came to life with four first-half sacks, after just seven sacks in the season’s first four games, doing so while the Seahawks were without left guard Mike Iupati due to knee and back injuries. Seahawks safety Jamal Adams (groin) also did not play.

Andrew Krammer did not travel to Seattle for Sunday’s game. He wrote this account after watching the television broadcast and participating in interviews via videoconference.